Light-emissive devices are well known and used for a wide variety of purposes, including area illumination and the representation of information. Traditionally, these light emissive devices rely on evacuated glass enclosures within which are special gases, phosphors, or filaments that emit light upon the application of a current or when stimulated with an electron. More recently, solid-state light-emissive devices have created a robust, long-lived, and practical light source using, for example, light emitting diodes, liquid crystal displays, and plasma displays.
Light emissive devices are useful in a variety of forms. Traditional forms include bulbs rounded in one or two dimensions, for example incandescent and fluorescent light bulbs. Neon lighting is often linear and is used to create lines of light through three dimensions. Large-format information displays such as cinemas rely upon curved screens to maintain a constant focal distance for viewers and to more readily simulate a real-world environment. Hence, conventional light-emissive and display devices are found with a variety of shapes, including flat, curved in one or two dimensions, and linear.
Conventional high-output light-emitting solid-state displays utilize light emitting diodes, typically point sources mounted into a substrate. Because individual devices are individually mounted, these devices can be mounted into a variety of substrates with a variety of shapes. However, because these devices utilize a collection of point light sources, they require additional optical devices such as mirrors and lenses for suitable area illumination. When applied to information display, individually mounted light emitting diodes are expensive and only suitable for low-resolution displays.
Flat-panel solid-state information display devices such as liquid crystal OLED and plasma display devices provide good resolution but are built upon flat panels, typically glass or silicon, and are not readily applied to curved displays.
The use of flexible substrates for displays, typically plastic, is also known. However, the quality, efficiency, and resolution of these displays is limited, as is their lifetime.
There is a need therefore for improved solid-state light emissive devices having a curved substrate for large-area illumination or information presentation.